GROCO Bronze High Speed Thru-Hull Fitting w/Nut 1-1/2". 1-1/2" Bronze High Speed Thru-Hull Fitting w/Nut Specifications for GROCO 1-1/2" Bronze High Speed Thru-Hull Fitting w/Nut: Manufacturer: GROCO Color: Black Features of GROCO 1-1/2" Bronze High Speed Thru-Hull Fitting w/Nut Designed for increased flow compared to standard Thru Hulls and with less drag NPSM / NPT combination thread C83600 Bronze Package Contents: GROCO 1-1/2" Bronze High Speed Thru-Hull Fitting w/Nut GROCO HSTH-1500-W: Bronze High Speed Thru-Hull Fitting w/Nut 1-1/2"